Regularly, HTML web sites created for the Internet are represented differently by different web browsers. This applies particularly also when the underlying HTML code is completely correct. Despite complying with standards stipulated by the W3C, web browsers have freedom of representation and optionally also different technical characteristics. Therefore, web designers must be able to find out as quickly as possible how their sites are displayed by different web browsers and viewed by different users correspondingly. Manual testing requires great effort, since many browsers must be installed on different operating systems and a specific web site would have to be accessed individually. In addition, different possible screen resolutions and web browser versions may play a role.
In order to obtain a representation of web sites that is as uniform as possible, conventionally, an analysis of the HTML source code of a web site is performed. For doing so, different tools for performing a syntax check are available via the Internet, for example. Here, it is to be noted, however, that a mere syntax check of the HTML code is usually not sufficient to make sure that a thereby described or defined web site is correctly represented in all common web browsers. In particular, the currently available W3C standards allow freedom of representation of HTML, which may possibly be the case also in the foreseeable future. Moreover, web browsers often exhibit internal errors that may lead to an incorrect-representation of web sites. Some manufacturers also decide to add own extensions in their own HTML creation tools and in their own web browsers, which extensions do not conform with the standard. Thus, a check of a web site by accessing it in several concrete web browsers is indispensable also in the case of a syntax check of the HTML code.